A Study of Longitudinal Cracking in Asphalt Pavement using CT Scanner

ABSTRACT Longitudinal cracking has been increasingly observed on asphalt concrete pavement in the world. Although over 20 years have passed since the longitudinal cracking was observed on asphalt concrete pavement in Europe and Japan, it has been believed that it was developed from the top of pavement (top down cracking) for highway and pavement on orthotropic steel deck bridge. In this study, sample cores were extracted using a diamond cutter from pavement on an expressway and orthotropic steel deck bridge, which had been in service for five years or thirteen years, and showed no longitudinal cracking on the surface. The cores were analyzed for longitudinal cracking in each layer using a newly developed micro-focus CT scanner and a three-dimensional void analysis program in order to examine where it comes from. This paper showed longitudinal cracking on asphalt pavement develops not from the surface or the bottom of pavement but from within the asphalt pavement.